[arin-ppml] Policy Proposal: Predicable IPv4 Run Out by Prefix Size

David Farmer farmer at umn.edu
Mon Jun 8 20:15:54 EDT 2009

On 8 Jun 2009 Pete Templin wrote:

> Member Services wrote:
> > This proposal is in the first stage of the Policy Development
> > Process. ARIN staff will perform the Clarity and Understanding step.
> > Staff does not evaluate the proposal at this time, their goal is to
> > make sure that they understand the proposal and believe the
> > community will as well. Staff will report their results to the ARIN
> > Advisory Council (AC) within 10 days.
> Can we somehow provide some clarity sooner rather than later?  At a
> high level, is this policy proposal really suggesting that 4-7
> large-enough ISPs could wipe out all of ARIN's IPv4 free pool?  

First of all as Owen points out, a single large enough ISP could wipe out all 
of ARIN's IPv4 free pool as the policies currently stands without something 
like this, even if you reduce the allocation window as in the other proposal.  I 
believe this to be a big problem and it is not equitable.  

I'm trying to avoid the word fair in this discussion because as was pointed out 
several times at ARIN XXIII there are multiple kinds of fairness.  I'm not really 
sure equitable is a much better word.  But in using the word I'm intending the 
following;  EQUITABILITY - The assessment of the fairness of a measure in 
its distribution of favorable or unfavorable impacts across the economic, 
environmental, social, and political interests that are affected.
You have the right idea, but not the right numbers,  with the proposed one 
quarter (1/4) ratio and starting at /8,  a geometric progression is created, 
such that if all allocations were of a maximum size available at the time, it 
would take 24 separate requests to wipe out the pool.  A ratio of one half 
(1/2) would require 13 maximum size requests, a ratio of one eighth (1/8) 
would require 44 maximum size requests, and a ratio one sixteenth (1/16) 
would require 80 maximum size requests.

See the following Google Docs spread sheet from more details, there are 
separate tabs for one half, one quarter, one eighth, and one sixteenth;


Please realize all requests will not be of a maximum size, the numbers above 
are purely the worst case scenario.  Also, exactly how much ARIN has in the 
IPv4 pool when this policy is triggered depends on when is triggered 
and if it is a request form ARIN that triggers it or a request from one of the 
other RIRs.  I think in theory it could be as much as three (3) /8s or as little 
as three (3) /10s receptively in the best or worst possible timing.  I suspect 
something a little more than /8 is probably about right.  But to make the math 
in the spread sheet easier I went with an exact /8 scenario.

> At a lower level, the composition of this proposal hurts my head, with
> things like "insure" vs. "ensure", or "at least until the maximum
> equals the minimum allocation or assignment size". 

Sorry that my bad grammar is causing your a head to hurt, I'll fix the 
insure/ensure.  Would "at least until the maximum decrements down to the  
minimum allocation or assignment size" be better?  If not, do you have a 
better suggestion?

Anything else making your head hurt?

Another way to think about this, it is what your grandma taught you, don't cut 
yourself to big of a pice of pie until everyone else has had some.  Since I'm 
not sure how ARIN would pick who's grandma to hire to implement this we 
need to write a policy that does much the same thing.

> Pete
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David Farmer                                      Email:farmer at umn.edu
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Networking & Telecomunication Services
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